Centralized Traffic Control (CTC) is a well-known system in the railroad industry that allows a dispatcher at a central dispatch office to monitor and control interlockings and traffic flow within a designated territory. (“Interlockings” is generally a signaling arrangement that prevents conflicting train movements through junctions and crossings.) Among other things, a CTC system allows a dispatcher, in some circumstances, to directly control the signal indications giving train movement authorities for a block of track. In addition, at least in some circumstances, a dispatcher may directly control switches, for example, to allow a train to move to a passing siding, crossover to an adjacent track, or turnout to an alternate track or route. A CTC system may also ensure that appliances, such as switches, are properly set before and during a train movement through a track block. In addition to receiving status information from signals and switches, the CTC system may also collect status information from other “wayside devices” such as rail integrity/track circuits and hazard detectors.
Positive train control (PTC) systems help to prevent train-to-train collisions, over-speed derailments, incursions into established work zone limits, and the movement of a train through a switch left in the wrong position. A PTC system is “interoperable” if it allows locomotives of a host railroad and a tenant railroad to communicate with and respond to the PTC system while supporting uninterrupted movements over property boundaries. Interoperable PTC (IPTC) systems have been mandated for some railroads under the Rail Safety Improvement Act of 2008 (Public Law 110-432 of 2008.
In addition, the computerized Interoperable Train Control System Management (ITCSM) system allows for the configuration and management of system assets across the operating territories of different railroads.